Self-assemblies of γ-CDs with pentablock copolymers PMA-PPO-PEO-PPO-PMA and endcapping via atom transfer radical polymerization of 2-methacryloyloxyethyl phosphorylcholine

• Jing Lin,
• Tao Kong,
• Lin Ye,
• Ai-ying Zhang and
• Zeng-guo Feng

Beilstein J. Org. Chem. 2015, 11, 2267–2277, doi:10.3762/bjoc.11.247

• -assembled with varying amounts of γ-CDs to prepare poly(pseudorotaxanes) (PPRs). When the concentration of γ-CDs was lower, the central PEO segment served as a shell of the micelles and was preferentially bent to pass through the γ-CD cavity to construct double-chain-stranded tight-fit PPRs characterized by

• single-chain-stranded with poly(methyl vinyl ether) (PMVE) [4] or poly(dimethylsiloxane) (PDMS) [5], but also double-chain-stranded with PEG and poly(ε-caprolactone) (PCL) [6]. Recently, Akashi et al. reported the single-chain-stranded inclusion complexation of γ-CDs with poly(methyl methacrylate) (PMMA

• -CD/PHEMA-PPO-PEO-PPO-PHEMA PPRs showing a mixed loose-fit (with PEO) and over-fit (with PHEMA) architecture, instead of the PEO-bent double-chain-stranded tight-fit ones like those of γ-CD/BrPEPBr PPRs [15][16]. However, attaching hydrophobic PMA to PPO-PEO-PPO renders the resulting amphiphilic

Loose-fit polypseudorotaxanes constructed from γ-CDs and PHEMA-PPG-PEG-PPG-PHEMA

• Tao Kong,
• Lin Ye,
• Ai-ying Zhang and
• Zeng-guo Feng

Beilstein J. Org. Chem. 2014, 10, 2461–2469, doi:10.3762/bjoc.10.257

• -CDs to give rise to tight-fit double-chain stranded polypseudorotaxanes (PPRs). After attaching the PHEMA, the resulting pentablock copolymer was single-chain stranded into the interior of γ-CDs to form more stable, loose-fit PPRs. The results of 1H NMR, WXRD, DSC, TGA, 13C CP/MAS NMR and FTIR

• first PPRs (comprised of γ-CD and PEG) as early as the 1990s. The γ-CD-based PPRs with designated supramolecular structure have been seldom prepared as compared with the α-CD- or β-CD-based PPRs [5][6][7][8][9][10][11][12][13]. Besides the typical double-chain stranded PPR showing a characteristic

• , instead of the PEG-bent, double-chain stranded, tight-fit ones as shown in Scheme 1. Results and Discussion Self-assembly of γ-CDs with a macroinitiator and a pentablock copolymer in aqueous solution As previously reported, a distal 2-bromoisobutyryl end-capped PEG was preferably bent to fit into the